Individual variation in adult attachment style in nonhuman primates, and its relation to infant attachment style, has yet to be fully explored. Titi monkeys (Plectorocebus cupreus) are one of the few primates known to form and maintain a pair bond during and beyond parenthood. We hypothesized titi monkeys would exhibit high individual variation in attachment behavior as adults and this variation could be predicted by infant attachment behavior . We measured behavioral responses to separation from the primary attachment figure, their father as an infant and their pair mate as an adult, in eleven coppery titi monkeys. A logistic regression with infant locomotive and vocal response to separation as the predictor variable for adult participation on an anxiety task in the absence of their pair mate revealed locomotion as a significant predictor of participation (B=-0.02, SE=0.006, z=-3.51, p<.001) but not infant vocalizations (B=-.003, SE=.004, Z=-0.634, p=.5). Infants that locomoted more during a brief separation were less likely as adults to participate in a food reward task in the absence of their pair mate. This model significantly outperformed the null (chi-squared = 13.72, df =2) and provides initial evidence that infant separation response in titi monkeys is predictive of adult separation response. An animal model for variation in adult attachment style provides an opportunity to explore a variety of biological and environmental influences on attachment behavior.